Disco 1 Prop shaft and vibrations.

So I've recently had a uj on the rear of the front prop go. Vibrating like hell. Also worth noting that when I checked it following some vibrations it was solid. But some wd40 and grease then it was awful. So quite deceiving.
Anyway I got a bearmach yolk and put it in. I marked the flanges but when I went to put it back the marks on the rear flange had disappeared. So the front ones lined up but I wasn't sure about the rear. The prop never came apart so the splines are in the same place. After replacing the yolk I took it for a drive but it vibrates horribly between 30-50 under acceleration. So I rotated the prop 180 on the rear flange and tried again. Slightly better but still bad!! I've seen people touch upon this but no difinitive answer. Any suggestions welcome!

I'm working from my defender 110 experience but I dont think its the rear prop that is set out of phase its the front.
Check the rear is in phase (both flanges sat aligned on the prop) because it may not have been and that the front is 45 degree out of phase.
After that you need to check the rest of the UJs aren't failing.

Bantam1 said:

I'm working from my defender 110 experience but I dont think its the rear prop that is set out of phase its the front.
Check the rear is in phase (both flanges sat aligned on the prop) because it may not have been and that the front is 45 degree out of phase.
After that you need to check the rest of the UJs aren't failing.

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Hi. Yh I checked all the ujs and they are all fine. I did do a little research and the rear prop is in line and the front is correct (about 45 and looks the same as ones you buy online) can't work it out.

I'd have a look at the transfer box and diff output bearings, with the prop off, see if they wobble.

Similar thing happened to me on the rear, disguised by the handbrake drum (Now X-Brake) the rear transfer box bearing wasn't a bearing and the nut holding the flange on wasn't tight at all ....

Just an idea. Can I remove the front pop and lock the diff and drive the car like normal? To confirm that it' the prop causing the issue?

Yes

UJ's can start to show their age when greased if they haven't been greased before in their life.
I had to change them on my defender when I first got it because as soon as I had pumped grease into them two of them began falling apart over the next few months.
I recall the rumble and final demise was ultimately all very sudden though.

If the gearbox flange bearings were failing surely you would have a seal problem too and oil leaking out!

Bantam1 said:

UJ's can start to show their age when greased if they haven't been greased before in their life.
I had to change them on my defender when I first got it because as soon as I had pumped grease into them two of them began falling apart over the next few months.
I recall the rumble and final demise was ultimately all very sudden though.

If the gearbox flange bearings were failing surely you would have a seal problem too and oil leaking out!

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Yh the seals on the transfer box seem fine but I have noticed there is a reasonable amount of oil coming from the rear diff now.. Quite a lot actually. Could this be the culprit? Pretty sure it wasn't like it when I change the uj.